As an oncologist, we insist on three levels of prevention for tumors: 1. Primary Prevention, also known as etiology prevention, is to take measures against the causative factors (or risk factors) when the disease has not yet occurred; 2. “The three early preventions are early detection, early diagnosis and early treatment. It is to prevent or slow down the development of disease and measures taken. 3, Tertiary Prevention (Tertiary Prevention) is also known as clinical prevention. Tertiary prevention can prevent disability and promote functional recovery, improve the quality of survival, prolong life expectancy and reduce the rate of death from disease. It is mainly symptomatic treatment and rehabilitation measures. Therefore, primary prevention is actually the most important and is the basic measure to prevent and eliminate cancer. According to the three departments of American Cancer Society (ACS), World Cancer Research Fund (WCRF) and American Institute for Cancer Research (AICR), they jointly issued a document recommending the lifestyle for cancer prevention, which is briefly summarized here in the hope that it will be helpful to all patients. Maintain normal weight BMI <25 kg/m2 (BMI is calculated as: weight/kg รท height2) Reduced risk of breast cancer in women This recommendation is based on the results of several recent randomized clinical trials. In a clinical trial (2905 women), women at high risk of developing breast cancer had a 44% reduction in risk of developing the disease after following the ACS recommendations. The Women's Health Initiative Watch (64,000 women) study found that a healthy diet (more fruits and vegetables, less meat, less alcoholic beverages) significantly reduced the risk of breast cancer in women, but it is important to note that a healthy diet did not reduce the risk of breast cancer in obese women. This is because BMI is a cancer risk factor in and of itself. Excess body fat triggers insulin resistance, and elevated levels of insulin and growth factors promote cancer development. Obesity also promotes the production of estrogen, which in turn is a stimulant for many cancers. In addition, fat secretes cytokines that promote inflammation. The key problem is that adults gain weight as they age, and this is impossible to prevent. So only good health management can be done. Increase physical activity Physical activity reduces the risk of cancer death Several observational studies have found that physical activity reduces the risk of breast, colorectal, and endometrial cancers. A study of U.S. and European populations found that those who exercised at the minimum recommended level of exercise - a metabolic equivalent (MET) of 7.5-15 per week - had a 20 percent lower risk of cancer death compared to those who were physically inactive. At the 2015 ASCO Annual Meeting, Professor Donald Abrams of the University of California noted that exercise can improve outcomes for patients with diagnosed cancer. A recent meta-analysis of breast and colorectal cancer survivors (50,000 patients) found that active exercise reduced breast cancer mortality and colorectal cancer mortality among survivors. This shows that it is even more important for cancer patients to adopt these cancer prevention recommendations after receiving treatment. Eat more vegetables, less meat Eating more vegetables and fruits reduces all-cause mortality and cardiovascular mortality in people, but is not associated with cancer-related mortality. In addition, studies have found that lean meats are not as bad as we think, at least from a cancer risk perspective. Processed meat products should be more of a concern than lean meats. Moderate alcohol consumption 1 standard glass of alcohol per day and no more Heavy alcohol consumption (more than 5 standard glasses of alcohol per day) is significantly associated with the development of 10 cancers: oropharyngeal, esophageal squamous epithelial, breast, larynx, colorectal, liver, stomach, gallbladder, pancreatic and lung cancers. In addition, studies have found that small amounts of alcohol (1 standard glass of alcohol per day) can increase the risk of oropharyngeal, esophageal squamous epithelial, and breast cancers. However, recent studies have reported that moderate alcohol consumption can prevent cancer. In addition, it is important not to lose sight of the fact that abstaining from alcohol is associated with higher overall mortality, as there is a trend toward higher cardiovascular morbidity among non-drinkers, so we cannot simply advocate that "abstaining from alcohol is healthy. Don't take vitamin supplements if you're not deficient A recent randomized clinical trial examined whether vitamin supplements could reduce the risk of cancer in a healthy population. However, the study brought about sobering results. For example, folic acid increased the risk of cancer, especially prostate and colorectal cancers; beta-carotene increased the risk of lung and stomach cancers; selenium increased the risk of non-melanoma skin cancer; and vitamin E increased the risk of prostate cancer. In summary, obesity, lack of exercise, and excessive alcohol intake are risk factors for cancer development and should be given significant attention. However, the evidence that dietary habits affect cancer is not conclusive, and the relationship between the two needs to be studied in depth.